RESUMEN
Color percept induction in synaesthetes by hearing words was previously shown to involve activation of visual and specifically color processing cortex areas. While this provides a rationale for the origin of the anomalous color percept the question of mechanism of this crossmodal activation remains unclear. We pursued this question with fMRI in color hearing synaesthetes by exposing subjects to words and tones. Brain activations in word condition accompanied by highly reliable color percepts were compared with activations in tone condition with only occasional color percepts and both contrasted to activations in normal subjects under the same stimulus conditions. This revealed that already the tone condition similar to the word condition caused abnormally high activations in various cortical areas even though synaesthetic percepts were more rare. Such tone activations were significantly larger than in normal subjects in visual areas of the right occipital lobe, the fusiform gyrus, and the left middle temporal gyrus and in auditory areas of the left superior temporal gyrus. These auditory areas showed strong word and tone activation alike and not the typically lower tone than word activation in normal subjects. Taken together these results are interpreted in favour of the disinhibited feedback hypothesis as the neurophysiological basis of genuine synaesthesia.
Asunto(s)
Corteza Auditiva/fisiología , Mapeo Encefálico , Percepción de Color/fisiología , Imagen por Resonancia Magnética , Percepción del Habla/fisiología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Lóbulo Occipital/fisiología , Trastornos de la Percepción/fisiopatología , Psicofísica , Lóbulo Temporal/fisiología , Adulto JovenRESUMEN
The integral classification of injuries (ICI) is a very logical, descriptive classification of fractures and dislocations of the human skeleton. By enumerating all 28 foot bones in relation to the three anatomical and functional regions of the foot, ie, hindfoot (81), midfoot (82), forefoot (83), from proximal to distal, and by introducing lowercase letters for the joints of the foot skeleton,the localization of the injury can be described precisely. The uppercase A defines extra-articular, B describes intra-articular and C is for fracture dislocations. By introducing the uppercase D, different dislocations can be described. By using additional lowercase Greek letters, the direction of a dislocation can be coded. For simple 'everyday' use, a fracture of the calcaneus(81.2) involving three joints can be described as a B3-fracture. For scientific or database coding purposes, one can describe in square brackets which joints or segments are involved and how they are injured in relation to three different subgroups representing first the tissue (bone, cartilage, capsule, and ligaments),second the kind of injury (three graduations of fracture, cartilage, or ligament damage), and third (three graduations) the extent of the dislocation or displacement. Following ten conventions, a complex foot trauma can be coded as precisely as a simple dislocation of the big toe.
Asunto(s)
Traumatismos de los Pies/clasificación , Calcáneo/lesiones , Huesos del Pie/lesiones , Fracturas Óseas/clasificación , Hallux/lesiones , Humanos , Luxaciones Articulares/clasificación , Articulaciones/lesiones , Ligamentos Articulares/lesiones , Huesos Metatarsianos/lesiones , Astrágalo/lesiones , Huesos Tarsianos/lesiones , Terminología como AsuntoRESUMEN
Catatonia is a psychomotor syndrome characterized by concurrent emotional, behavioral, and motor anomalies. Pathophysiological mechanisms of psychomotor disturbances may be related to abnormal emotional-motor processing in prefrontal cortical networks. We therefore investigated prefrontal cortical activation and connectivity patterns during emotional-motor stimulation using functional magnetic resonance imaging (FMRI). We investigated 10 akinetic catatonic patients in a postacute state and compared them with 10 noncatatonic postacute psychiatric controls (age-, sex-, diagnosis-, and medication-matched) and 10 healthy controls. Positive and negative pictures from the International Affective Picture System were used for emotional stimulation. FMRI measurements covered the whole frontal lobe, activation signals in various frontal cortical regions were obtained, and functional connectivity between the different prefrontal cortical regions was investigated using structural equation modeling. Catatonic patients showed alterations in the orbitofrontal cortical activation pattern and in functional connectivity to the premotor cortex in negative and positive emotions compared to psychiatric and healthy controls. Catatonic behavioral and affective symptoms correlated significantly with orbitofrontal activity, whereas catatonic motor symptoms were rather related to medial prefrontal activity. It is concluded that catatonic symptoms may be closely related to dysfunction in the orbitofrontal cortex and consequent alteration in the prefrontal cortical network during emotional processing. Because we investigated postacute patients, orbitofrontal cortical alterations may be interpreted as a trait marker predisposing for development of catatonic syndrome in schizophrenic or affective psychosis.
Asunto(s)
Imagen por Resonancia Magnética , Rigidez Muscular/diagnóstico , Rigidez Muscular/fisiopatología , Corteza Prefrontal/fisiopatología , Enfermedad Aguda , Adulto , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Habituación Psicofisiológica , HumanosRESUMEN
Various prefrontal cortical regions have been shown to be activated during emotional stimulation, whereas neurochemical mechanisms underlying emotional processing in the prefrontal cortex remain unclear. We therefore investigated the influence of the GABA-A potentiator lorazepam on prefrontal cortical emotional-motor spatio-temporal activation pattern in a combined functional magnetic resonance imaging/magnetoencephalography study. Lorazepam led to the reversal in orbito-frontal activation pattern, a shift of the early magnetic field dipole from the orbito-frontal to medial prefrontal cortex, and alterations in premotor/motor cortical function during negative and positive emotional stimulation. It is concluded that negative emotional processing in the orbito-frontal cortex may be modulated either directly or indirectly by GABA-A receptors. Such a modulation of orbito-frontal cortical emotional function by lorazepam has to be distinguished from its effects on cortical motor function as being independent from the kind of processing either emotional or nonemotional.
Asunto(s)
Cognición/fisiología , Emociones/fisiología , Moduladores del GABA/administración & dosificación , Lorazepam/administración & dosificación , Corteza Prefrontal/fisiología , Ácido gamma-Aminobutírico/metabolismo , Adulto , Cognición/efectos de los fármacos , Método Doble Ciego , Femenino , Humanos , Imagen por Resonancia Magnética , Magnetoencefalografía , Masculino , Estimulación Luminosa , Corteza Prefrontal/efectos de los fármacosRESUMEN
Recognition of sound patterns must be largely independent of level and of masking or jamming background sounds. Auditory patterns of relevance in numerous environmental sounds, species-specific vocalizations and speech are frequency modulations (FM). Level-dependent activation of the human auditory cortex (AC) in response to a large set of upward and downward FM tones was studied with low-noise (48 dB) functional magnetic resonance imaging at 3 Tesla. Separate analysis in four territories of AC was performed in each individual brain using a combination of anatomical landmarks and spatial activation criteria for their distinction. Activation of territory T1b (including primary AC) showed the most robust level dependence over the large range of 48-102 dB in terms of activated volume and blood oxygen level dependent contrast (BOLD) signal intensity. The left nonprimary territory T2 also showed a good correlation of level with activated volume but, in contrast to T1b, not with BOLD signal intensity. These findings are compatible with level coding mechanisms observed in animal AC. A systematic increase of activation with level was not observed for T1a (anterior of Heschl's gyrus) and T3 (on the planum temporale). Thus these areas might not be specifically involved in processing of the overall intensity of FM. The rostral territory T1a of the left hemisphere exhibited highest activation when the FM sound level fell 12 dB below scanner noise. This supports the previously suggested special involvement of this territory in foreground-background decomposition tasks. Overall, AC of the left hemisphere showed a stronger level-dependence of signal intensity and activated volume than the right hemisphere. But any side differences of signal intensity at given levels were lateralized to right AC. This might point to an involvement of the right hemisphere in more specific aspects of FM processing than level coding.